#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <getopt.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <asm/types.h>
#include <linux/videodev2.h>
#include <linux/fb.h>
#define CLEAR(x) memset (&(x), 0, sizeof (x))
#define IMG_WIDTH (640)
#define IMG_HIGHT (480)

struct buffer {
	void *start;
	size_t length;
};

static char *dev_name = NULL;
static int fd = -1;
struct buffer *buffers = NULL;
static unsigned int n_buffers = 0;
static int time_in_sec_capture = 5;
static int fbfd = -1;
static struct fb_var_screeninfo vinfo;
static struct fb_fix_screeninfo finfo;
static char *fbp = NULL;
static long screensize = 0;

static void errno_exit (const char *s)
{
	fprintf (stderr, "%s error %d, %s\n", s, errno, strerror (errno));
	exit (EXIT_FAILURE);
}

static int xioctl (int fd, int request, void *arg)
{
	int r;
	do {
		r = ioctl (fd, request, arg);
	} while (-1 == r && EINTR == errno);
	return r;
}

inline int clip(int value, int min, int max)
{
	return (value > max ? max : value < min ? min : value);
}
#define Y0  0   
#define U   1   
#define Y1  2   
#define V   3   
  
#define R   0   
#define G   1   
#define B   2 
int yuv422_rgb24(unsigned char *yuv_buf, unsigned char *rgb_buf, unsigned int width, unsigned int height)  
{  
    int yuvdata[4];  
    int rgbdata[3];  
    unsigned char *rgb_temp;  
    unsigned int i, j;  
  
    rgb_temp = rgb_buf;  
    for (i = 0; i < height * 2; i++) {  
        for (j = 0; j < width; j+= 4) {  
            /* get Y0 U Y1 V */  
            yuvdata[Y0] = *(yuv_buf + i * width + j + 0);  
            yuvdata[U]  = *(yuv_buf + i * width + j + 1);  
            yuvdata[Y1] = *(yuv_buf + i * width + j + 2);  
            yuvdata[V]  = *(yuv_buf + i * width + j + 3);  
  
            /* the first pixel */  
            rgbdata[R] = yuvdata[Y0] + (yuvdata[V] - 128) + (((yuvdata[V] - 128) * 104 ) >> 8);  
            rgbdata[G] = yuvdata[Y0] - (((yuvdata[U] - 128) * 89) >> 8) - (((yuvdata[V] - 128) * 183) >> 8);  
            rgbdata[B] = yuvdata[Y0] + (yuvdata[U] - 128) + (((yuvdata[U] - 128) * 199) >> 8);  
  
            if (rgbdata[R] > 255)  rgbdata[R] = 255;        
            if (rgbdata[R] < 0) rgbdata[R] = 0;            
            if (rgbdata[G] > 255)  rgbdata[G] = 255;        
            if (rgbdata[G] < 0) rgbdata[G] = 0;            
            if (rgbdata[B] > 255)  rgbdata[B] = 255;        
            if (rgbdata[B] < 0) rgbdata[B] = 0;            
              
//            *(rgb_temp++) = rgbdata[R] ;  
//            *(rgb_temp++) = rgbdata[G];  
//            *(rgb_temp++) = rgbdata[B]; 
            *(rgb_temp++) =( ((rgbdata[G]& 0x1C) << 3) | (rgbdata[B] >> 3) );
            *(rgb_temp++) =( (rgbdata[R]& 0xF8) | (rgbdata[G] >> 5) );



 
              
            /* the second pix */   
            rgbdata[R] = yuvdata[Y1] + (yuvdata[V] - 128) + (((yuvdata[V] - 128) * 104 ) >> 8);  
            rgbdata[G] = yuvdata[Y1] - (((yuvdata[U] - 128) * 89) >> 8) - (((yuvdata[V] - 128) * 183) >> 8);  
            rgbdata[B] = yuvdata[Y1] + (yuvdata[U] - 128) + (((yuvdata[U] - 128) * 199) >> 8);  
          
            if (rgbdata[R] > 255)  rgbdata[R] = 255;        
            if (rgbdata[R] < 0) rgbdata[R] = 0;            
            if (rgbdata[G] > 255)  rgbdata[G] = 255;        
            if (rgbdata[G] < 0) rgbdata[G] = 0;            
            if (rgbdata[B] > 255)  rgbdata[B] = 255;        
            if (rgbdata[B] < 0) rgbdata[B] = 0;        
      
//            *(rgb_temp++) = rgbdata[R];  
//            *(rgb_temp++) = rgbdata[G];  
//            *(rgb_temp++) = rgbdata[B]; 
            *(rgb_temp++) =( ((rgbdata[G]& 0x1C) << 3) | (rgbdata[B] >> 3) );
            *(rgb_temp++) =( (rgbdata[R]& 0xF8) | (rgbdata[G] >> 5) ); 
          
        }  
    }  
    return 0;  
} 
int compress_yuyv_to_rgb(unsigned char *framebuffer, unsigned char *tempbuffer,
	int width, int height)

{
	unsigned char *yuyv = framebuffer;//vd->framebuffer为开辟的640*480*2字节的内存空间
	int z = 0 , i = 0, j = 0;

	for(i = 0 ; i < 320 ; i++) //宽度的像素点数  480*0.6=288  //此处最大值可以增加1

	{

		for (j = 0; j < 480; j++) { //长度的像素点数 640*0.75=480 //此处值如果减半，即240，则最后yuyv += 4相应的改为yuyv += 8，可达到双屏的效果，而且，外循环的272可以为480，扩大了摄像头的采集范围
			int r, g, b;
			int y, u, v;
			short rgb;

			//此处代码没研究明白，可能跟采样相关吧，大概执行为(yuy1v): yuvy1uvy2u1v1y3u1v1....

			if (!z) {
				y = yuyv[0] << 8;
			} else {
				y = yuyv[2] << 8;
			}
			u = yuyv[1] - 128;
			v = yuyv[3] - 128;
			//yuv转rgb888

			r = (y + (359 * v)) >> 8;

			g = (y - (88 * u) - (183 * v)) >> 8;

			b = (y + (454 * u)) >> 8;

			r = (r > 255) ? 255 : ((r < 0) ? 0 : r); // RGB的范围为0~255，0为最弱，255为最亮
			g = (g > 255) ? 255 : ((g < 0) ? 0 : g);
			b = (b > 255) ? 255 : ((b < 0) ? 0 : b);
			//rgb888转rgb565
			r >>= 3; //RGB565格式中red占5位，green占6位，blue占5位，故需进行移位
			g >>= 2;
			b >>= 3;

			rgb = (r << 11) | (g << 5) | (b); //生成一个2个字节长度的像素点，即rgb565
			//赋给lcd映射的buffer
			*tempbuffer++ = (char)rgb;   //第一个字节
			*tempbuffer++ = (char)(rgb >> 8); //第二个字节

			if (z++) {
				z = 0;
				yuyv += 4; //yuyv为四个，所以下一像素点从第五个字节开始
			}
		}
		yuyv += (640 - 480) * 2; //换行，即裁剪，因为摄像头采集的是640*480的，横屏640，但lcd横屏为480，多余的就裁剪了。
	}
}
int convertyuv422torgb565(unsigned char *inbuf, unsigned char *outbuf, int width, int height)
{
	int rows, cols, rowwidth;
	int y, u, v, r, g, b, rdif, invgdif, bdif;
	int size;
	unsigned char *YUVdata, *RGBdata;
	int YPOS, UPOS, VPOS;

	YUVdata = inbuf;
	RGBdata = outbuf;

	rowwidth = width >> 1;
	size = width * height * 2;
	YPOS = 0;
	UPOS = YPOS + size / 2;
	VPOS = UPOS + size / 4;

	for(rows = 0; rows < height; rows++) {
		for(cols = 0; cols < width; cols++) {
			u = YUVdata[UPOS] - 128;
			v = YUVdata[VPOS] - 128;

			// v + 0.79*v
			rdif = v + ((v * 103) >> 8);
			//0.34375*u + 0.34375*v
			invgdif = ((u * 88) >> 8) + ((v * 183) >> 8);
			//u + 0.7734375*u
			bdif = u + ( (u * 198) >> 8);

			r = YUVdata[YPOS] + rdif;
			g = YUVdata[YPOS] - invgdif;
			b = YUVdata[YPOS] + bdif;
			r = r > 255 ? 255 : (r < 0 ? 0 : r);
			g = g > 255 ? 255 : (g < 0 ? 0 : g);
			b = b > 255 ? 255 : (b < 0 ? 0 : b);

			// *(RGBdata++) = ( ((g & 0x1C) << 3) | ( b >> 3) );
			// *(RGBdata++) = ( (r & 0xF8) | ( g >> 5) );
			// r = 0;//255;
			// g = 0;
			// b = 0;
			*(RGBdata++) = ( ((g & 0x1C) << 3) | ( b >> 3) );
			*(RGBdata++) = ( (r & 0xF8) | ( g >> 5) );
			// *(RGBdata++) = ( ((g & 0x1C) << 3) | ( b >> 3) );
			// *(RGBdata++) = ( ((r & 0xF8) >> 1) | ( g >> 6) );

			YPOS++;

			if(cols & 0x01) {
				UPOS++;
				VPOS++;
			}
		}
		if((rows & 0x01) == 0) {
			UPOS -= rowwidth;
			VPOS -= rowwidth;
		}
	}
	return 1;
}
static void process_image (const void *p)
{


	//ConvertYUVToRGB32

	unsigned char *in = (char *)p;
	int width = IMG_WIDTH;
	int height = IMG_HIGHT;
	int istride = 1280;
	int x, y, j;
	int y0, u, y1, v, r, g, b;
	long location = 0;

	// convertyuv422torgb565(in, fbp, width, height);
	// compress_yuyv_to_rgb(in, fbp, width, height);
	yuv422_rgb24(in, fbp, width, height);
	return ;
	for ( y = 100; y < height + 100; ++y) {
		for (j = 0, x = 100; j < width * 2 ; j += 4, x += 2) {
			// for ( y = 0; y < height + 0; ++y) {
			// for (j = 0, x = 100; j < width * 2 ; j += 4, x += 2) {

			location = (x + vinfo.xoffset) * (vinfo.bits_per_pixel / 8) +
			           (y + vinfo.yoffset) * finfo.line_length;

			y0 = in[j];
			u  = in[j + 1] - 128;
			y1 = in[j + 2];
			v  = in[j + 3] - 128;

			r = (298 * y0 + 409 * v + 128) >> 8;
			g = (298 * y0 - 100 * u - 208 * v + 128) >> 8;
			b = (298 * y0 + 516 * u + 128) >> 8;

			fbp[ location + 0] = clip(b, 0, 255);
			fbp[ location + 1] = clip(g, 0, 255);
			fbp[ location + 2] = clip(r, 0, 255);
			fbp[ location + 3] = 255;
			r = (298 * y1 + 409 * v + 128) >> 8;
			g = (298 * y1 - 100 * u - 208 * v + 128) >> 8;
			b = (298 * y1 + 516 * u + 128) >> 8;

			fbp[ location + 4] = clip(b, 0, 255);
			fbp[ location + 5] = clip(g, 0, 255);
			fbp[ location + 6] = clip(r, 0, 255);
			fbp[ location + 7] = 255;
		}
		in += istride;
	}

}

static int read_frame (void)
{
	struct v4l2_buffer buf;
	unsigned int i;

	CLEAR (buf);
	buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	buf.memory = V4L2_MEMORY_MMAP;

	if (-1 == xioctl (fd, VIDIOC_DQBUF, &buf)) {
		switch (errno) {
		case EAGAIN:
			return 0;
		case EIO:



		default:
			errno_exit ("VIDIOC_DQBUF");
		}
	}

	assert (buf.index < n_buffers);
	assert (buf.field == V4L2_FIELD_NONE);
	process_image (buffers[buf.index].start);
	if (-1 == xioctl (fd, VIDIOC_QBUF, &buf)) {
		errno_exit ("VIDIOC_QBUF");
	}

	return 1;
}

static void run (void)
{
	unsigned int count;
	int frames;
	frames = 30 * time_in_sec_capture;

	while (1 || frames-- > 0) {
		for (;;) {
			fd_set fds;
			struct timeval tv;
			int r;
			FD_ZERO (&fds);
			FD_SET (fd, &fds);


			tv.tv_sec = 2;
			tv.tv_usec = 0;

			r = select (fd + 1, &fds, NULL, NULL, &tv);

			if (-1 == r) {
				if (EINTR == errno) {
					continue;
				}
				errno_exit ("select");
			}

			if (0 == r) {
				fprintf (stderr, "select timeout\n");
				exit (EXIT_FAILURE);
			}

			if (read_frame ()) {
				break;
			}

		}
	}
}

static void stop_capturing (void)
{
	enum v4l2_buf_type type;

	type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	if (-1 == xioctl (fd, VIDIOC_STREAMOFF, &type)) {
		errno_exit ("VIDIOC_STREAMOFF");
	}
}

static void start_capturing (void)
{
	unsigned int i;
	enum v4l2_buf_type type;

	for (i = 0; i < n_buffers; ++i) {
		struct v4l2_buffer buf;
		CLEAR (buf);

		buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		buf.memory = V4L2_MEMORY_MMAP;
		buf.index = i;

		if (-1 == xioctl (fd, VIDIOC_QBUF, &buf)) {
			errno_exit ("VIDIOC_QBUF");
		}
	}

	type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

	if (-1 == xioctl (fd, VIDIOC_STREAMON, &type)) {
		errno_exit ("VIDIOC_STREAMON");
	}

}

static void uninit_device (void)
{
	unsigned int i;

	for (i = 0; i < n_buffers; ++i)
		if (-1 == munmap (buffers[i].start, buffers[i].length)) {
			errno_exit ("munmap");
		}

	if (-1 == munmap(fbp, screensize)) {
		printf(" Error: framebuffer device munmap() failed.\n");
		exit (EXIT_FAILURE) ;
	}
	free (buffers);
}


static void init_mmap (void)
{
	struct v4l2_requestbuffers req;


	//mmap framebuffer
	fbp = (char *)mmap(NULL, screensize, PROT_READ | PROT_WRITE, MAP_SHARED , fbfd, 0);
	if ((int)fbp == -1) {
		printf("Error: failed to map framebuffer device to memory.\n");
		exit (EXIT_FAILURE) ;
	}
	memset(fbp, 0, screensize);
	CLEAR (req);

	req.count = 4;
	req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	req.memory = V4L2_MEMORY_MMAP;

	if (-1 == xioctl (fd, VIDIOC_REQBUFS, &req)) {
		if (EINVAL == errno) {
			fprintf (stderr, "%s does not support memory mapping\n", dev_name);
			exit (EXIT_FAILURE);
		} else {
			errno_exit ("VIDIOC_REQBUFS");
		}
	}

	if (req.count < 4) {    //if (req.count < 2)
		fprintf (stderr, "Insufficient buffer memory on %s\n", dev_name);
		exit (EXIT_FAILURE);
	}

	buffers = calloc (req.count, sizeof (*buffers));

	if (!buffers) {
		fprintf (stderr, "Out of memory\n");
		exit (EXIT_FAILURE);
	}

	for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
		struct v4l2_buffer buf;

		CLEAR (buf);

		buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		buf.memory = V4L2_MEMORY_MMAP;
		buf.index = n_buffers;

		if (-1 == xioctl (fd, VIDIOC_QUERYBUF, &buf)) {
			errno_exit ("VIDIOC_QUERYBUF");
		}


		buffers[n_buffers].length = buf.length;
		buffers[n_buffers].start = mmap (NULL, buf.length, PROT_READ | PROT_WRITE , MAP_SHARED, fd, buf.m.offset);
		if (MAP_FAILED == buffers[n_buffers].start) {
			errno_exit ("mmap");
		}
	}

}



static void init_device (void)
{
	struct v4l2_capability cap;
	struct v4l2_cropcap cropcap;
	struct v4l2_crop crop;
	struct v4l2_format fmt;
	unsigned int min;


	// Get fixed screen information
	if (-1 == xioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
		printf("Error reading fixed information.\n");
		exit (EXIT_FAILURE);
	}

	// Get variable screen information
	if (-1 == xioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
		printf("Error reading variable information.\n");
		exit (EXIT_FAILURE);
	}
	printf("fb w=%d h=%d deep=%d\n", vinfo.xres , vinfo.yres, vinfo.bits_per_pixel);
	screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;


	if (-1 == xioctl (fd, VIDIOC_QUERYCAP, &cap)) {
		if (EINVAL == errno) {
			fprintf (stderr, "%s is no V4L2 device\n", dev_name);
			exit (EXIT_FAILURE);
		} else {
			errno_exit ("VIDIOC_QUERYCAP");
		}
	}

	if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
		fprintf (stderr, "%s is no video capture device\n", dev_name);
		exit (EXIT_FAILURE);
	}

	if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
		fprintf (stderr, "%s does not support streaming i/o\n", dev_name);
		exit (EXIT_FAILURE);
	}



	CLEAR (cropcap);

	cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	cropcap.defrect.width = cropcap.defrect.width / 2;
	cropcap.defrect.height = cropcap.defrect.height / 2;

	if (0 == xioctl (fd, VIDIOC_CROPCAP, &cropcap)) {
		crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		crop.c = cropcap.defrect;

		if (-1 == xioctl (fd, VIDIOC_S_CROP, &crop)) {
			switch (errno) {
			case EINVAL:
				break;
			default:
				break;
			}
		}
	} else {     }

	printf("################################\n");
	printf("cropping bounds \n");
	printf("\tleft\t%d\n", cropcap.bounds.left);
	printf("\ttop\t%d\n", cropcap.bounds.top);
	printf("\twidth\t%d\n", cropcap.bounds.width);
	printf("\theight\t%d\n", cropcap.bounds.height);
	printf("cropping defrect \n");
	printf("\tleft\t%d\n", cropcap.defrect.left);
	printf("\ttop\t%d\n", cropcap.defrect.top);
	printf("\twidth\t%d\n", cropcap.defrect.width);
	printf("\theight\t%d\n", cropcap.defrect.height);
	printf("cropping pixelaspect\n");
	printf("\tnumerator\t%d\n", cropcap.pixelaspect.numerator);
	printf("\tdenominator\t%d\n", cropcap.pixelaspect.denominator);
	CLEAR (fmt);

	fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	fmt.fmt.pix.width = IMG_WIDTH;
	fmt.fmt.pix.height = IMG_HIGHT;
	fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
	fmt.fmt.pix.field = V4L2_FIELD_NONE;

	if (-1 == xioctl (fd, VIDIOC_S_FMT, &fmt)) {
		errno_exit ("VIDIOC_S_FMT");
	}




	init_mmap ();

}

static void close_device (void)
{
	if (-1 == close (fd)) {
		errno_exit ("close");
	}
	fd = -1;
	close(fbfd);
}

static void open_device (void)
{
	struct stat st;

	if (-1 == stat (dev_name, &st)) {
		fprintf (stderr, "Cannot identify '%s': %d, %s\n", dev_name, errno, strerror (errno));
		exit (EXIT_FAILURE);
	}

	if (!S_ISCHR (st.st_mode)) {
		fprintf (stderr, "%s is no device\n", dev_name);
		exit (EXIT_FAILURE);
	}

	//open framebuffer
	fbfd = open("/dev/fb0", O_RDWR);
	if (fbfd == -1) {
		printf("Error: cannot open framebuffer device.\n");
		exit (EXIT_FAILURE);
	}

	//open camera
	fd = open (dev_name, O_RDWR | O_NONBLOCK, 0);

	if (-1 == fd) {
		fprintf (stderr, "Cannot open '%s': %d, %s\n", dev_name, errno, strerror (errno));
		exit (EXIT_FAILURE);
	}
}

static void usage (FILE *fp, int argc, char **argv)
{
	fprintf (fp,
	         "Usage: %s [options]\n\n"
	         "Options:\n"
	         "-d | --device name Video device name [/dev/video]\n"
	         "-h | --help Print this message\n"
	         "-t | --how long will display in seconds\n"
	         "",
	         argv[0]);
}

static const char short_options [] = "d:ht:";
static const struct option long_options [] = {
	{ "device", required_argument, NULL, 'd' },
	{ "help", no_argument, NULL, 'h' },
	{ "time", no_argument, NULL, 't' },
	{ 0, 0, 0, 0 }
};

struct bb {
	int a ;
	int b;
};
int main (int argc, char **argv)
{
	struct bb f, c;
	f.a = 2;
	f.b = 3;
	c = f;
	printf("%d %d\n", c.a , c.b);

	dev_name = "/dev/video0";

	for (;;) {
		int index;
		int c;

		c = getopt_long (argc, argv, short_options, long_options, &index);
		if (-1 == c) {
			break;
		}

		switch (c) {
		case 0:
			break;

		case 'd':
			dev_name = optarg;
			break;

		case 'h':
			usage (stdout, argc, argv);
			exit (EXIT_SUCCESS);
		case 't':
			time_in_sec_capture = atoi(optarg);
			break;

		default:
			usage (stderr, argc, argv);
			exit (EXIT_FAILURE);
		}
	}

	open_device ();

	init_device ();

	start_capturing ();
	printf("run...\n");
	run ();
	printf("stop...\n");
	stop_capturing ();
	printf("uninit_device...\n");
	uninit_device ();
	printf("close_device...\n");
	close_device ();

	exit (EXIT_SUCCESS);

	return 0;
}

